To provide drinking water in most areas of the United States, water is taken from aquifers located deep within the ground. The water is brought to a treatment facility where it is made potable by extensive treatment processes. The potable water then is pumped through water distribution systems to the end user.
After the water is used, it then flows by gravity from the end user through a central sewage collection system into sewer pump stations that pump the waste water to a sewer treatment facility where the water, after an extensive treatment process, is disposed of through canals and rivers. In some cases, the extent of treatment of the waste water is sufficient that the treated waste water is pumped back to the end user through an extensive piping system so that this treated water can be reused for irrigation purposes.